ES2834629T3 - Polymeric microparticles - Google Patents

Abstract

Microparticles having a polymeric shell, comprising, based on the total weight of the microparticles: a) from 1 to 20% by weight of at least one HASE-type acrylic copolymer comprising: - at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group; - at least one hydrophobic nonionic monomer having a vinyl group capable of being polymerized; and - at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain; b) from 4 to 95% by weight of at least one solid / liquid phase change material that has a phase transition temperature Tf1 varying from 35 ° C to 90 ° C, selected from the waxes of natural origin, waxes of synthetic origin or mixtures thereof; c) from 4 to 95% by weight of at least one solid / liquid phase change material having a phase transition temperature Tf2 less than or equal to 30 ° C, for example less than or equal to 20 ° C, selected from the group consisting of vegetable oils, fatty alcohols, fatty acids, and mixtures thereof; and d) optionally, 4 to 95% by weight of an active agent selected from the group consisting of fragrance molecules, flavors, opacifying agents, moisturizing agents, softening agents, cooling agents, tinctures, plasticizers, slimming agents, active ingredients. pharmaceuticals, inks, pigments, agrochemical active ingredients, herbicides, antiseptics, detergents, enzymes, antifoaming agents, whitening agents, optical brighteners, biocides, UV stabilizers, antioxidants, corrosion inhibitors, fungicides and antibacterial agents.

Description

DESCRIPTION

Polymeric microparticles

Field of the invention

The present invention relates to the technical field of encapsulation, for example encapsulation of active agents, by means of acrylic copolymers of the HASE type.

Background of the invention

Microencapsulation techniques are being increasingly developed and used in various technical fields (eg pharmaceutical, cosmetic, textile, food processing, agrochemical, detergent or paint industry). Numerous encapsulation procedures are known. Thus, it has been proposed to encapsulate active agents by means of in situ polymerization, by means of solvent extraction or also by means of coacervation.

Such techniques make it possible to encapsulate active agents of different chemical nature, for example, hydrophilic or hydrophobic active agents, such as fragrance molecules, pharmaceutical active ingredients, cosmetic agents, photochromic or photo-luminous pigments, and the like.

The publication by Atterholt et al. (1999), for example, is related to the encapsulation of insect pheromones for the control of insect populations and as an alternative to the use of insecticides. The document describes various encapsulation systems based on the presence of paraffin wax and / or a combination of soybean oil / vitamin E that is presented as feasible to suppress the volatility of pheromones.

The publication of Delmas et al. (2012) is also related to encapsulation using soybean oil, waxes or a mixture of both.

In the prior art, encapsulating active agents by means of HASE-type acrylic polymers has also been provided.

In particular, document WO 2008/146119 (Coatex) describes the use of HASE-type emulsions to trap fragrance molecules by varying the pH of the mixture.

Also, document WO 2014/96622 (Coatex) describes the use of an acrylic copolymer of the HASE type and of at least one solid / liquid phase change material having a phase transition temperature ranging from 20 to 90 ° C to prepare microcapsules of an active agent, the presence of a phase change material makes it possible to improve the mechanical strength of the microcapsules. Although they are suitable for a number of fields of use, the microparticles obtained according to the formula described in the following document have, in some other applications, the disadvantage of being excessively hard, breaking or lacking in flexibility. This is in the particular case when the microparticles have to remain on the surfaces on which they are deposited, for example a textile or a rough surface. Furthermore, the microparticles of the prior art do not make it possible to encapsulate some active ingredients. Document US 2014/0178485 A1 describes microparticles with a polymeric shell, comprising an acrylic copolymer of the HASE type and a material with a solid / liquid phase change having a phase transition temperature between 35 and 70 ° C.

Brief description of the invention

The present invention relates to microparticles having a polymeric shell, and also to aqueous dispersions comprising said microparticles. The microparticles have a polymeric shell that comprises:

to. at least one acrylic copolymer of the HASE type;

b. at least one solid / liquid phase change material having a transition temperature Tfi ranging from 35 ° C to 90 ° C;

c. at least one solid / liquid phase change material having a transition temperature Tf ² less than or equal to 30 ° C;

d. optionally at least one active agent.

The microparticles according to the invention are as described in the claims.

The present invention also relates to the use of these microparticles or the aqueous dispersions containing them to release an active agent in response to a change in pH, a change in temperature and / or frictions and / or over time.

The present invention also relates to the use of these microparticles or the aqueous dispersions that comprise them as a hydrophobicizing agent for textiles or in the preparation of cosmetic, agrochemical, paint, textile, detergent or paper products.

The present disclosure also relates to a process for the preparation of an aqueous dispersion of microparticles, and also a process for the preparation of microparticles having a polymeric shell, as described above.

Definitions

In the present description of the present invention, the term "HASE" is an acronym for " Hydrophobically Modified Alkali Soluble Emulsions" (Hydrophobically Modified Alkali-Soluble Emulsions).

In the description of the present invention, the term "HASE-type acrylic copolymer" denotes linear or cross-chain copolymers comprising acid groups and hydrophobic groups. HASE-type copolymers result from the copolymerization of anionic monomers, such as (meth) acrylic acids, of hydrophobic nonionic monomers and of hydrophobic associative macromonomers. At low pH (typically less than 5) and with the addition of a base, the HASE-type acrylic copolymer is insoluble in water and is present in the form of an aqueous dispersion. When a base is added, the anionic groups are neutralized and the copolymer dissolves in the water.

In the description of the present invention, the expression "solid / liquid phase change material has a phase transition temperature Tfi greater than or equal to 20 ° C" denotes a material that has the ability to reversibly change state. at a temperature Tfi greater than 20 ° C, for example, within a temperature range of 20 to 90 ° C. This phase change material participates in the composition of the microparticles of the present invention is solid at a temperature lower than its phase transition temperature Tfi and liquid at a temperature higher than its phase transition temperature Tfi. "Phase transition temperature Tf ¹ " denotes the melting point of the material or the temperature that corresponds to the solid / liquid transition of the phase change material.

In the description of the present invention, the expression "solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C" denotes a material that has the ability to change state of reversibly at a temperature Tf ² less than 20 ° C. This phase change material participates in the composition of the microparticles of the present invention is solid at a temperature lower than its phase transition temperature Tf ² and liquid at a temperature higher than its phase transition temperature Tf ² . "Phase transition temperature Tf ² " denotes the melting point of the material or the temperature corresponding to the solid / liquid transition of the phase change material.

In the present invention, the phase change materials that participate in the particle composition of the present invention are chosen from the point of view of the subsequent use of the particles.

In the description of the present invention, the term "active agent" or "active ingredient" denotes any compound that has an advantage in being encapsulated.

In the description of the present invention, unless otherwise indicated, the percentages expressed represent percentages by weight and are expressed based on the total weight of the reference element. For example, when it is indicated that a copolymer comprises 10% of a monomer, it is understood that the copolymer comprises 10% by weight of this monomer, based on the total weight of this copolymer.

In the description of the present invention, the expression "at least one" denotes one or more compounds (for example: one or more acrylic copolymers of the HASE type, one or more phase change materials, one or more active agents) , such as a mixture of 2 to 5 compounds.

In describing the present invention, the term "microparticles" denotes particles having an average size ranging from 0.2 µm to a few tens of microns, such as 0.2 to 100 µm, or 0.2 to 70 pm, or from 1 to 40 pm. When the microparticles are spherical particles, the average size of the particles denotes the average diameter of the particles. When the particles are not spherical, that is, they have a longer dimension and a shorter dimension, the average particle size denotes the size of the longest dimension of the particles. The size of the particles can be measured according to procedures well known to a person skilled in the art, such as by means of laser granulometry.

"Microparticles having a polymeric shell" or "composite microparticles" or "microcapsules" are understood to mean microparticles having an outer shell made of a co-polymer according to the invention and optionally including an active agent according to to the invention.

In the description of the present invention, the letters "n", "m" and "p" denote whole numbers or decimals (in this case, they represent average values).

In describing the present invention, the claimed range limits are included within the scope of the invention. For example, if a group comprises between 10 and 40 carbon atoms, that group is capable of comprising 10 or 40 carbon atoms.

Detailed description of the invention

The microparticles having a polymeric shell of the present invention are provided in the form of more or less spherical structures capable of conforming or adhering, at least in part, to the surfaces that receive them (eg, textile or external surface).

The microparticles having a polymeric shell of the present invention can be provided in the form of aqueous dispersions or they can be provided in the form of solid microparticles that are more or less soft or rigid according to the requirements of the application.

The microparticles of the present invention have the distinctive feature of comprising at least two different types of solid / liquid phase change materials. More specifically, these materials differ in their solid / liquid phase transition temperature Tf. To use two types of phase change materials as essential constituents of the microcapsules according to the invention makes it possible to obtain microcapsules that have different physical properties from the microcapsules of the prior art, in particular those described in document WO 2014/96622. These microcapsules can in particular have a degree of softness that makes them more suitable for a number of applications.

Furthermore, the base constituents of these microcapsules make it possible to obtain a more flexible and adjustable microencapsulation system that is appropriate for the expected release requirements. In particular, by specifically choosing at least two phase change materials (for example, as a function of their respective phase transition temperatures) and by fixing their respective amounts within the microcapsule composition , the release temperature of its active ingredient is adjusted as a function of the application requirements.

It is also possible to more easily adjust the shear strength of the microparticles.

Furthermore, the combination of the (at least) two phase change materials has the advantage of allowing a better dissolution of the active ingredient, when the second is present, within the composition, and potentially a better release.

The system described in the present patent application makes it possible to encapsulate a great variety of active ingredients and / or increase the content of ingredients in the microparticles.

The microparticles having a polymeric shell of the present invention comprise:

to. at least one acrylic copolymer of the HASE type,

b. at least one solid / liquid phase change material having a transition temperature Tf ¹ ranging from 35 ° C to 90 ° C,

c. at least one solid / liquid phase change material that has a transition temperature Tf ² less than or equal to 30 ° C, for example, less than or equal to 20 ° C, conditional on Tf ² being less than Tf ¹ , and d. optionally at least one active agent.

The microparticles according to the invention are as described in the claims.

HASE type acrylic copolymer:

HASE-type acrylic copolymers form the outer shell of the microparticles of the present invention. According to the embodiments of the invention, the HASE-type acrylic copolymers that participate in the composition of the microparticles of the present invention comprise the following monomers:

i. at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group; ii. at least one hydrophobic nonionic monomer having a vinyl group capable of being polymerized; and iii. at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain.

Anionic Monomers i. that have a vinyl group capable of being polymerized and a carboxyl group are monomers that have a negative charge in basic aqueous solution. Anionic monomers having a polymerizable vinyl group and a carboxyl group are, for example, chosen from acrylic acid and / or methacrylic acid.

Nonionic monomers ii. Having a vinyl group capable of being polymerized are monomers that have neither a positive nor a negative charge in aqueous solution. Nonionic hydrophobic monomers having a vinyl group capable of being polymerized are, for example, chosen from esters, amides or nitriles of acrylic or methacrylic acids or of acrylonitrile, vinyl acetate, styrene, methylstyrene, diisobutylene, vinylpyrrolidone or vinylcaprolactam. In a very particular way, the nonionic hydrophobic monomers that have a vinyl group capable of being polymerized can be chosen from C ¹ -C ⁸ ethyl acrylates or from CrC8 alkyl methacrylates, such as methyl acrylate, ethyl acrylate, or acrylate. butyl, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, or mixtures thereof. More particularly, nonionic hydrophobic monomers having a vinyl group capable of being polymerized can be chosen from ethyl acrylate, butyl acrylate, ethyl methacrylate or mixtures thereof.

The alkoxylated associative macromonomer iii. Which has a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain can have the following formula (I):

(I) R - A - R '

in which:

- A represents a polymer chain consisting of:

- m alkylene oxide units of the formula -CH ² CHR ¹ O- where Ri represents an alkyl group comprising 1 to 4 carbon atoms, for example a methyl or ethyl group, and m varies from 0 to 150,

- p alkylene oxide units of the formula -CH ² CHR ² O- where R ² represents an alkyl group comprising 1 to 4 carbon atoms, for example a methyl or ethyl group, and m varies from 0 to 150, - n units of ethylene oxide where n ranges from 0 to 150, or from 10, or 15, to 150, or from 10, or 15, to 100, or from 15 to 50, or from 15 to 30,

where m + n + p> 4, or m + n + ps 5, and where the alkylene oxide units of the formula -CH ² CHR ¹ O-, the alkylene oxide units of the formula -CH ² CHR ² O- and ethylene oxide units are found in blocks, staggered, or random;

- R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic or crotonic esters; Y

- R 'represents a straight or branched hydrocarbon chain comprising from 6 to 40 carbon atoms or from 7 to 35 carbon atoms or from 8 to 22 carbon atoms or from 10 to 20 carbon atoms (limits included) or a substituted or unsubstituted cycloalkyl or aryl group comprising from 6 to 100 carbon atoms or from 6 to 60 carbon atoms.

The groups R ¹ and R ² can be identical or different.

In specific embodiments, the alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

wherein R, R 'and A are as defined above, with n representing a number of ethylene oxide units ranging from 15 to 150 or from 15 to 50 or from 15 to 30.

In specific embodiments, the alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

wherein R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic and methacrylic esters and A and R 'are as defined in the previously described embodiments. In specific embodiments, the alkoxylated associative macromonomer has a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

wherein R 'represents a straight or branched hydrocarbon chain comprising from 8 to 20 carbon atoms or from 8 to 16 carbon atoms, preferably a straight hydrocarbon chain of 8 to 22 carbon atoms (for example, C8, C ^12, C ^{16 to 18,} C ^22), or a branched chain of 12 to 20 carbon atoms (eg, C ^12, C ^16, C ²⁰⁾ and A and R are as defined in the embodiments described above.

In specific embodiments, the alkoxylated associative macromonomer has a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

wherein A, R, and R 'are as defined in the embodiments described above, with m and p representing 0, respectively.

In specific embodiments, the alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

in which:

- A is as defined in the embodiments described above, with myp representing 0, respectively, and n varying from 15 to 150 or from 15 to 50 or from 15 to 30 (thus A represents a polymer chain made up of 15 150 or 15 to 50 or 15 to 30 ethylene oxide units);

- R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic or crotonic esters, preferably belonging to the group of acrylic and methacrylic esters; Y

- R 'represents a straight or branched hydrocarbon chain comprising from 6 to 40 carbon atoms, or from 7 to 35 carbon atoms or from 8 to 22 carbon atoms.

In specific embodiments, the alkoxylated associative macromonomer having a vinyl group capable of being polymerized and having a hydrophobic hydrocarbon chain has the following formula (I):

(I) R - A - R '

in which:

- A is as defined in the embodiments described above, with myp representing 0, respectively and n ranges from 15 to 150 or from 15 to 50 or from 15 to 30 (thus A represents a polymer chain formed from 15 to 150 or 15 to 50 or 15 to 30 ethylene oxide units);

- R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic and methacrylic esters; Y

- R 'represents a chain of straight hydrocarbon or branched comprising from 8 to 22 carbon atoms, for example, a straight chain containing 8 to 22 carbon atoms (for example, C8, C ^12, C ^{16 to 18,} C ²² ), or a branched chain of 12 to 20 carbon atoms (eg, C ¹² , C ¹⁶ , C ²⁰ ).

In specific embodiments, the acrylic copolymers that participate in the composition of the particles of the present invention comprise:

i. at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group chosen from acrylic, methacrylic acid or a mixture thereof;

ii. at least one hydrophobic nonionic monomer having a vinyl group capable of being polymerized selected from ethyl acrylate, methyl methacrylate, butyl acrylate or mixtures thereof; Y

iii. at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and having a hydrocarbon chain of the following formula (I):

(I) R - A - R '

wherein A, R and R 'are as defined in the embodiments described above.

In specific embodiments, the acrylic copolymers that participate in the composition of the particles of the present invention comprise:

i. at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group chosen from acrylic acid, methacrylic acid, and the mixture thereof;

ii. at least one nonionic hydrophobic monomer having a vinyl group capable of being polymerized selected from ethyl acrylate, methyl methacrylate, butyl acrylate or mixtures thereof;

iii. at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and having a hydrophobic hydrocarbon chain of formula (I):

(I) R - A - R '

in which:

- A is as defined in the embodiments described above, with m and p representing 0, respectively, and n varying from 15 to 150 or from 15 to 50 or from 15 to 30 (thus, A represents a polymer chain formed from 15 to 150 or 15 to 50 or 15 to 30 ethylene oxide units);

- R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic, methacrylurethane, vinylurethane or crotonic esters, preferably to the group of acrylic and methacrylic esters;

- R 'represents a straight or branched hydrocarbon chain comprising 8 to 22 carbon atoms, for example, a straight hydrocarbon chain of 8 to 22 carbon atoms (for example, C8, C ¹² , C ^16-18 , C ²² ), or a branched chain of 12 to 20 carbon atoms (eg C ¹² , C ¹⁶ , C ²⁰ ).

The acrylic copolymers that participate in the composition of the particles of the present invention typically comprise:

i. from 20% to 65% or from 30% to 45% by weight of at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group;

ii. 35% to 75% or 45% to 60% by weight of at least one nonionic hydrophobic monomer having a vinyl group capable of being polymerized; Y

iii. from 0.5% to 15% or from 1% to 13% by weight of at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain, more particularly of an alkoxylated associative macromonomer of the following formula (I):

(I) R - A - R '

wherein A, R and R 'are defined in the embodiments described above.

In specific embodiments, the acrylic copolymers that participate in the composition of the particles of the present invention comprise:

i. from 20% to 65% or from 30% to 45% by weight of at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group chosen from acrylic acid, methacrylic acid or the mixture thereof;

ii. 35% to 75% or 45% to 60% by weight of at least one nonionic hydrophobic monomer having a vinyl group capable of being polymerized selected from ethyl acrylate, methyl methacrylate, butyl acrylate or mixtures thereof ; Y

iii. 0.5% to 15% or 1% to 13% by weight of at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and having a hydrophobic hydrocarbon chain of formula (I):

(I) R - A - R '

in which:

- A is as defined in the embodiments described above, with myp representing 0, respectively, and n varying from 15 to 150 or from 15 to 50 or from 15 to 30 (thus A represents a polymer chain made up of 15 150 or 15 to 50 or 15 to 30 ethylene oxide units);

- R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic, methacrylurethane, vinylurethane or crotonic esters, preferably to the group of acrylic and methacrylic esters; Y

- R 'a chain of straight hydrocarbon or branched comprising from 8 to 22 carbon atoms, for example, a chain straight hydrocarbon having 8 to 22 carbon atoms (for example, C8, C ^12, C ^16-18, C ²² ), or a branched chain of 12 to 20 carbon atoms (eg, C ¹² , C ¹⁶ , C ²⁰ ).

The HASE-type acrylic copolymers that participate in the composition of the particles of the present invention result from the copolymerization of the monomers described above. They can be prepared according to the procedures described in documents WO 2011/104599, WO 2011/104600 and EP 1,778,797.

During polymerization, a chain transfer agent can be added in order to control the molecular weight of the copolymer. The chain transfer agent can be chosen from mercaptans, such as ethyl mercaptan, n-propyl mercaptan, n-butyl mercaptan, isobutyl mercaptan, t-butyl mercaptan, n-amyl mercaptan, isoamyl mercaptan, mercaptan of t-amyl, n-hexyl mercaptan, cyclohexyl mercaptan, n-octyl mercaptan, n-decyl mercaptan or n-dodecyl mercaptan.

Phase change material having a phase transition temperature Tfi

The particles of the present invention comprise at least one solid / liquid phase change material having a phase transition temperature Tfi ranging from 35 ° C to 90 ° C.

The phase change materials that participate in the composition of the particles of the present invention can be chosen from waxes of natural or synthetic origin. Naturally occurring waxes include animal waxes, vegetable waxes, and mineral waxes.

Animal and vegetable waxes are generally formed from a mixture of lipids having a long hydrocarbon chain, such as fatty acids, fatty alcohols or fatty acid or fatty alcohol esters, even ethers. "Long hydrocarbon chains" is understood to mean hydrocarbon chains having, for example, 10 to 40 carbon atoms. Animal and vegetable waxes typically have a phase transition temperature ranging from 25 ° C to 90 ° C. Examples of vegetable waxes include carnauba wax, candelilla wax, sugar cane or esparto wax or shea butter. Examples of animal waxes include beeswax or lanolin.

Mineral waxes, including paraffin waxes, are generally made up of saturated hydrocarbons having a straight chain comprising, for example, 20 to 40 carbon atoms. Mineral waxes typically have a phase transition temperature ranging from 25 ° C to 90 ° C. Examples of mineral wax include ceresin, ozocerite, paraffin waxes, and microcrystalline waxes. Examples of paraffin waxes include heneicosan, the melting point of which is 40.5 ° C, eicosan, the melting point of which is 36.1 ° C, and nonadecane, the melting point of which is 32.1 °. C.

Synthetic waxes are generally made up of long hydrocarbon chains free of functional groups. Examples of waxes of synthetic origin include polymers based on polyethylene and polymers based on polyalkylene glycol, such as polymers based on polyethylene glycol and polymers based on polypropylene glycol.

Also mentioned are silicone-based or organosilylated waxes of synthetic origin.

Phase change material having a phase transition temperature Tf ²

The particles of the present invention comprise at least one plasticizer material. According to one embodiment, this phase change material has a phase transition temperature Tf ² less than or equal to 30 ° C, subject to this phase transition temperature Tf ² being less than the phase transition temperature Tfi of the other phase change material present in the microparticles of the invention. For example, this phase change material has the ability to reversibly change state at a temperature less than or equal to 25 ° C, for example, <20 ° C, or 18 ° C or 15 ° C.

The phase change materials that participate in the composition of the particles of the present invention can be selected from polar oils, non-polar oils, or mixtures thereof.

In the category of "non-polar oil", particular mention is made of silicone oils, such as linear or cyclic polydimethylsiloxanes (PDMS) which are liquid at room temperature; polydimethylsiloxanes comprising alkyl, alkoxy or phenyl groups that are liquid at room temperature, whose groups are end and / or at the end of the silicone chain and have from 2 to 24 carbon atoms; liquid phenylated silicones, such as phenyl trimethicones, phenyl dimethicones, phenyl (trimethylsiloxy) diphenylsiloxanes, diphenyl dimethicones, diphenyl (methyldiphenyl) trisiloxanes or (2-phenylethyl) trimethylsiloxysilicates; linear or branched liquid hydrocarbons or fluorocarbons of synthetic or mineral origin, such as paraffin oils and their derivatives, petroleum jelly, polydecenes, hydrogenated polyisobutene or squalane; and mixtures thereof.

In the category of "polar oil", mention is made in particular of vegetable oils, synthetic oils, synthetic esters and ethers, fatty alcohols, fatty acids and their mixture.

Examples of these oils are in particular:

- vegetable hydrocarbon oils that have a high content of triglycerides formed from fatty acid esters (C8 to C ²⁴ fatty acids) and glycerol, the fatty acids of which may have varied chain lengths, it being possible for the chains to be straight or branched and saturated or unsaturated; These oils are in particular wheat germ oil, corn oil, marigold oil, shea oil, castor oil, sweet almond oil, linseed oil, macadamia oil, apricot oil, soybean oil, Rapeseed, Cottonseed Oil, Alfalfa Oil, Poppy Oil, Red Kuri Pumpkin Oil, Sesame Oil, Pumpkin Oil, Avocado Oil, Hazelnut Oil, Grapeseed Oil, Black Currant Oil, evening primrose oil, millet oil, barley oil, quinoa oil, olive oil, rye oil, safflower oil, candil or kukui tree oil, passionflower oil or musk rose oil;

- C8 to C ²⁶ fatty alcohols, such as oleic alcohol;

- fatty acids having 12 to 22 carbon atoms, such as oleic acid, linoleic acid or linolenic acid;

- mixtures thereof.

Active agent

The microparticles of the present invention comprise at least one active agent.

The active agent can be selected from the group consisting of fragrances, fragrance molecules, flavors, opacifying agents, moisturizing agents, softening agents, cooling agents, colorants, plasticizers, thinning agents, active pharmaceutical ingredients, inks, pigments, active agrochemical ingredients, herbicides, antiseptics, detergents, enzymes, antifoaming agents, whitening agents, optical brighteners, biocides, UV stabilizers, antioxidants, corrosion inhibitors, fungicides, and antibacterial agents. Mention is made, but means of indication, of fragrances and fragrance molecules, of terpene derivatives, such as limonene, cintronelal, terpineol and menthol.

In some embodiments of the present invention, the active agent is a fragrance or a fragrance molecule. According to one embodiment of the present invention, the active agent is not a pheromone or a semi-chemical agent.

The microparticles of the present invention

The microparticles of the present invention comprise, based on the total weight of the microparticles:

- from 1 to 20% or from 1 to 15% or from 1 to 10% by weight of at least one acrylic copolymer of the HASE type as described above;

- from 4 to 95%, or from 4 to 75% or from 4 to 50% by weight, of at least one solid / liquid phase change material having a phase transition temperature Tf ¹ ranging from 35 ° C to 90 ° C, as described above; - from 4 to 95% by weight of at least one solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C, and

- from 4 to 95%, or from 24 to 95% or from 49 to 95%, by weight of at least one active agent as described above.

In another embodiment of the present invention, the weight ratio of the solid / liquid phase change material having a phase transition temperature Tf ¹ ranging from 35 ° C to 90 ° C and the solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C is between 1/10 and 10/1.

The microparticles of the present invention may be provided in the form of an aqueous dispersion of particles or they may be provided in a solid form, ie in the form of solid granules (or microcapsules). Thus, the present invention relates to aqueous dispersions comprising microparticles as described above and solid microparticles with a composition as described in the present specification.

Aqueous microparticle dispersions may comprise from 1 to 70% by weight of microparticles.

The microparticles of the present invention have a composition such that they release the contents of the polymeric shell in response to a change in pH, a change in temperature and / or under the action of friction and / or under the action of time.

If these microparticles do not contain an active agent, because they are, for example, in order to render textile hydrophobic, shear (or friction) of these microparticles results in the destructuring of the particles. The second then releases its contents on the surface of the textile to be treated. The contents of the microcapsules are in this case chosen such that, for example, they are predominantly made of solid / liquid phase change materials of a fatty nature (wax / oil type mixture).

The microparticles may alternatively contain at least one active agent. In this case, the microparticles of the present invention are such that they make it possible to release the encapsulated active agent in response to a change in pH, a change in temperature and / or shear / friction.

The microparticles of the present invention therefore have minimal mechanical strength, such that they maintain their integrity after being prepared. It is also possible to adjust the composition of the microparticles in order to increase the shear strength. Thus, according to this aspect, the microparticles of the present invention are microparticles of "controlled mechanical force".

The concentrations of HASE-type acrylic copolymer, phase change materials and / or active agent can be adjusted in order to obtain microparticles that are soft / rigid of a greater or lesser extent in order to adjust their resistance to actions. shear.

More particularly, the amount of solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C is chosen so that the microcapsules containing them have a mechanical force that can be greater or lesser as a function of the desired release effect (rapid or very delayed).

The dispersions or microparticles of the present invention can be used in the field of cosmetology, for example, to formulate lotions, shampoos, creams, deodorants, makeup compositions or care compositions. Mention is made in this regard in particular of encapsulation of fragrances, essential oils, opacifiers, moisturizing agents, softening agents, cooling agents or thinning agents.

The microparticle dispersions of the present invention can be used in the field of the textile industry, for example, in the manufacture of clothes, pantyhose, bottoms or gloves. Mention may be made in this connection in particular of the encapsulation of fragrances, slimming agents, antiperspirants or antibacterial agents. The dispersions or microparticles are then applied to various textiles.

The dispersions or microparticles of the present invention can be used in the field of paints or dyes: pigments or resins can in particular be encapsulated.

The microparticles of the present invention can be used in the field of the paper industry (encapsulation of inks or fragrance molecules) or the manufacture of detergents (encapsulation of fragrance, antifoam or bleaching agents).

Thus, the solid microparticles or aqueous dispersions of microparticles of the present invention can be used in the preparation of cosmetic, agrochemical, detergent, paint, textile or paper products.

Procedures for the preparation of the microparticle dispersion and the microparticles

An object of the present disclosure also relates to a process for the preparation of an aqueous dispersion of microparticles and to a process for the preparation of microparticles having a polymeric shell, as described above. The solid microparticles of the present invention are generally produced from an aqueous dispersion of microparticles.

The aqueous dispersions of microparticles can be prepared by means of a process that comprises the following steps:

a) preparation of an aqueous solution comprising:

- at least one acrylic copolymer of the HASE type dissolved in said aqueous solution by means of a base;

- at least one solid / liquid phase change material having a phase transition temperature Tfi greater than or equal to 20 ° C, said phase change material is present in or has been introduced into the aqueous solution at a temperature greater than its phase transition temperature Tf1;

- at least one solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C, for example less than or equal to 20 ° C; Y

- optionally, at least one active agent; Y

b) coacervation of the HASE-type acrylic polymer so as to result in said aqueous dispersions of microparticles.

When the solid / liquid phase change material is said to be "present in the aqueous solution at a temperature greater than its transition temperature Tf ¹ ", it is understood that all the constituents in the aqueous solution are at a temperature greater than the temperature transition phase of the phase change material.

When the solid / liquid phase change material is described as having "been introduced into the aqueous solution at a temperature greater than its phase transition temperature Tf ¹ ", it is understood that the material has been added at a temperature greater than its phase transition temperature Tf ¹ but that the water, the base, the HASE-type copolymer and the active agent may be at a temperature of less than this phase transition temperature Tfi. The final aqueous solution comprising the HASE-type acrylic copolymer, the base, the active agent and the two phase change materials in this way generally has a temperature lower than the phase transition temperature Tfi.

In general, the solid / liquid phase change material has a phase transition temperature Tf ¹ greater than or equal to 20 ° C, alone or as a mixture with the active agent and the second phase change material (which has a phase transition temperature Tf ² less than or equal to 30 ° C), is heated to a temperature greater than its phase transition temperature Tfi and introduced to a temperature greater than its phase transition temperature Tf ¹ in a solution comprising the other constituents of the microcapsules, this aqueous solution generally has a temperature lower than the phase transition temperature Tfi of the phase change material.

In step a), the base added in an amount that makes it possible to dissolve the acrylic copolymer of the HASE type in the aqueous solution.

The base employed in the process is typically an organic or an inorganic base. The base can, for example, be selected from sodium hydroxide, ammonia, potassium hydroxide and 2-amino-2-methyl-1-propanol.

Publications by Jenkins et al., 2002 ( J. Phys. Chem. B, 2002, 106, 1195-1204) and Horiuchi et al., 1998 ( Can. J. Chem., 76, 1779-1787) describe the phenomenon of dissolution of HASE polymers during the addition of a base.

According to embodiments of the invention, the amount of base used to dissolve the copolymer is such that the pH of the aqueous solution is greater than or equal to 6.5, or greater than or equal to 7, or greater than or equal to 7.5.

According to other embodiments of the invention, as a function of the type of base used, in particular if the base used is sodium hydroxide, the amount of base used to dissolve the copolymer is such that the molar ratio (nOH / nCOOH ) from the number of hydroxyl groups contributed by the base (nOH ') to the number of carboxyl groups carried by the HASE-type acrylic copolymer (nCOOH) is greater than 0.3, or greater than 0.4, or greater than 0 , 45 and preferably less than 1.2. The number of carboxyl groups carried by the HASE-type copolymer can be determined by means of procedures known to a person skilled in the art, such as by titration.

According to embodiments of the invention, the aqueous solution of step a) is prepared with mixing.

The coacervation stage of the HASE-type acrylic polymer results in the aqueous dispersions of microparticles (stage b)) is carried out once the aqueous solution is at a temperature lower than the phase transition temperature of the exchange material of Tfi phase, that is to say after cooling of the aqueous solution.

The coacervation can be carried out by means of the addition of salts, such as sodium chlorides, or alternatively by means of the addition of an acid.

In some embodiments of step b) of the process, the coacervation is carried out by means of the addition of an acid. The acid used in the process can in particular be chosen from an organic or an inorganic acid. More particularly, the acid can be chosen from phosphoric acid, hydrochloric acid, acetic acid, citric acid, D-gluconic acid, glutamic acid and ascorbic acid.

In some embodiments of step b) of the process, the amount of acid used to carry out the coacervation is such that the pH of the dispersion is less than or equal to 6.5 or less than or equal to 6.3.

In other embodiments of step b) of the process, as a function of the type of acid used, in particular if the acid used is acetic acid, the amount of acid added is such that the molar ratio (nH3O + / nCOOH) of the number of protons contributed by the acid (nH3O +) to the number of carboxyl groups carried by the acrylic copolymer of the HASE type (nCOOH) is greater than 0.1, or greater than 0.15, or greater than 0.2 and less than 1.

According to embodiments of the invention, the addition of salt or acid is carried out with mixing.

The coacervation (or precipitation of the HASE-type acrylic polymer makes it possible to form a polymeric shell that constitutes the outer shell of the microparticles.

In some embodiments, the aqueous solution comprising the dissolved HASE-type acrylic copolymer, the active agent, and the solid / liquid phase change material (step a)) is prepared according to the following steps:

a1) preparation of an aqueous solution comprising the acrylic copolymer of the HASE type dissolved by means of a base;

a2) preparation of a mixture comprising the active agent and the phase change material, said mixture prepared at a temperature higher than the phase transition temperature of the phase change material or subsequently heated to a temperature higher than the phase transition temperature of the phase change material; Y

a3) introduction of the mixture, for example, with mixing, obtained in step a2) to the aqueous solution obtained in step a1).

It is observed that, according to these embodiments, during step a3):

- the mixture obtained in step a2) is at a temperature higher than the phase transition temperature of the phase change material, for example, at a temperature between the phase transition temperature of the phase change material and the temperature heating of the mixture a2);

- the aqueous solution obtained in step a1) is at a temperature lower than the phase transition temperature of the phase change material.

According to embodiments of the invention, the introduction of the mixture obtained in step a2) to the aqueous solution obtained in step a1) is carried out with mixing.

In other embodiments, the aqueous solution comprising the dissolved HASE-type acrylic copolymer, the active agent, and the solid / liquid phase change material (step a)) can be prepared according to the following steps:

a1) preparation of an aqueous solution comprising the HASE type acrylic copolymer dissolved by means of a base, at least one active agent and at least one phase change material; Y

a2) heating the aqueous solution obtained in step a1) to a temperature higher than the transition temperature of the phase change material.

According to embodiments of the invention, the aqueous solution is prepared (step a1)) with mixing or is mixed after being prepared. In this case, it can be mixed before, during or after heating (step a2)), but before carrying out step b).

According to these embodiments, the order of introduction of the HASE-type copolymer, the base, the active agent and the phase change material so as to result in the aqueous solution of step a1) is not important.

In this way the HASE type acrylic copolymer, water and base can be mixed together in the first stage. A second mixture comprising the phase change material and the active agent can be added to this mixture, in order to obtain the aqueous solution of step a1).

Alternatively, the HASE-type copolymer, water, phase change material and active agent can be mixed together, without the preliminary submixing step, to deliver the aqueous solution of step a1). Thus, according to the present invention, the aqueous dispersions of particles can be prepared by means of a process comprising the following steps:

a1) preparation of an aqueous solution comprising a base and at least one acrylic copolymer of the HASE type, more particularly a copolymer of the HASE type as described above;

a2) preparation of a mixture comprising at least one active agent and at least the two phase change materials, said mixture prepared at a temperature higher than the phase transition temperature Tfi of the phase change material (the phase transition temperature Tfi which is greater than or equal to 20 ° C);

a3) introducing the mixture obtained in step a2) to the aqueous solution obtained in step a1); and b) coacervation of the HASE-type acrylic copolymer so as to result in aqueous dispersions of the particles.

Alternatively, the aqueous dispersions of the particles of the present disclosure can be prepared by means of a process comprising the following steps:

a1) preparation of an aqueous solution comprising a base, at least one active agent, at least the two phase change materials and at least one acrylic copolymer of the HASE type, more particularly a copolymer of the HASE type as described above;

a2) heating the aqueous solution obtained in step a1) to a temperature higher than the temperature Tfi of the phase change material (the phase transition temperature Tf ¹ which is greater than or equal to 20 ° C); and b) coacervation of the HASE-type acrylic copolymer so as to result in aqueous dispersions of particles.

Solid microparticles can be obtained after drying the microparticle dispersions obtained in step b).

The HASE-type acrylic copolymer, the phase change materials and the active agent employed in the processes of the present invention may be as described in the description of the present invention. The processes used in the preparation of the microparticles of the present invention are environmentally friendly because no use of organic solvents is made.

Use of the dispersion or microparticles

An object of the present invention also relates to the use of microparticles according to the invention or of aqueous dispersions of microparticles according to the invention in the preparation of cosmetic, agrochemical, paint, textile, detergent or paper products.

Another object of the present invention relates to the use of microparticles according to the invention or of aqueous dispersions of microparticles according to the invention to render hydrophobic textiles.

Yet another object of the present invention relates to the use of microparticles according to the invention or of aqueous dispersions of microparticles according to the invention to release an active agent in response to a change in pH, a change in temperature and / or frictions and / or over time.

The present invention also relates to a hydrophobicizing agent for textiles consisting of microparticles according to the invention or of aqueous dispersions of microparticles according to the invention.

EXAMPLES EXAMPLE 1

This example illustrates the preparation of a microparticle dispersion according to the invention without an active principle.

Preparation of the acrylic copolymer HASE

The acrylic copolymer according to the invention is prepared according to procedures known to a person skilled in the art by means of a mercaptan-type chain transfer agent.

This co-polymer is made of:

35.5% by weight of methacrylic acid,

52.4% by weight of ethyl acrylate,

12.0% by weight of a macromonomer of formula (I) in which:

- myp = 0,

- n = 30,

- R represents a methacrylic ester,

- R 'represents a branched hydrocarbon chain comprising 12 carbon atoms.

Test 1-1: Preparation of a microparticle dispersion according to the present invention Preparation of an aqueous solution

7.5 g of the HASE co-polymer (polymerized at 30.8% in water) are dissolved in 59.25 g of water in the presence of 3.8 g of 10% sodium hydroxide solution by mixing in a mechanical mixer at a temperature of 40 ° C.

15.75 g of paraffin wax sold by Sigma-Aldrich under the reference Paraffin Wax 327204 (Tfi = 53 to 57 ° C) are mixed with 47.25 g of commercial marigold oil (Tf ² <0 ° C). The mixture is stirred and heated to a temperature of about 90 ° C.

The liquid paraffin wax / wonder oil mixture (at a temperature between Tfi and 80 ° C) is introduced into an aqueous solution of the HASE co-polymer using a peristaltic pump.

Coacervation

6.44 g of ^{4% H 3} PO ⁴ are added to the aqueous HASE copolymer solution to which the paraffin wax / wonder oil mixture has been added. A dispersion that is white in color with a pH of 6.2, the diameter D50% of the particles of which is 5.3 pm.

Test 1-2: Preparation of a microparticle dispersion outside the invention

Preparation of an aqueous solution

15 g of HASE co-polymer (polymerized at 30.8% in water) are dissolved in 118 g of water in the presence of 7.62 g of 10% sodium hydroxide solution by means of mixing in a mechanical mixer at a temperature of 40 ° C.

126 g of paraffin wax sold by Sigma-Aldrich under the reference Paraffin Wax 327204 (Tfi = 53 to 57 ° C) are mixed and heated to a temperature of approximately 90 ° C.

The liquid paraffin wax (at a temperature between Tfi and 80 ° C) is introduced into the aqueous HASE copolymer solution using a peristaltic pump.

Coacervation

12.88 g of a ^{4% H 3} PO ⁴ solution are added to the aqueous HASE copolymer solution to which the paraffin wax has been added. Under these conditions, lumps are obtained; it is not possible to obtain a microparticle dispersion as in test 1-1.

EXAMPLE 2

This example illustrates the preparation of two microparticle dispersions according to the invention without an active ingredient.

Preparation of the acrylic copolymer HASE

The acrylic copolymer according to the invention is prepared according to procedures known to a person skilled in the art by means of a mercaptan-type chain transfer agent.

This co-polymer is made of:

35.5% by weight of methacrylic acid,

52.4% by weight of ethyl acrylate,

12.0% by weight of the macromonomer of formula (I) in which:

- m and p = 0,

- n = 30,

- R represents a methacrylic ester,

- R 'represents a branched hydrocarbon chain comprising 12 carbon atoms.

Test 2-1: Preparation of a microparticle dispersion according to the present invention Preparation of an aqueous solution

7.5 g of the HASE co-polymer (polymerized at 30.8% in water) are dissolved in 59.25 g of water in the present of 3.8 g of 10% sodium hydroxide solution by means of mixing in a mechanical mixer at a temperature of 40 ° C.

15.75 g of beeswax sold by Sigma-Aldrich (Tfi = 61 to 65 ° C) is mixed with 47.25 g of commercial marigold oil. The mixture is stirred and heated to a temperature of about 80 ° C.

This liquid ternary mixture (at a temperature between Tfi and 80 ° C) is introduced into the aqueous HASE copolymer solution using a peristaltic pump.

Coacervation

6.44 g of ^{4% H 3} PO ⁴ solution are added to the aqueous HASE copolymer solution to which the liquid ternary mixture has been added. A dispersion that is white in color is obtained.

Test 2-2: Preparation of a microparticle dispersion according to the present invention Preparation of an aqueous solution

7.5 g of HASE copolymer (polymerized at 30.48% in water) are dissolved in 59.25 g of water in the presence of 3.8 g of 10% sodium hydroxide solution by mixing in a mechanical mixer at a temperature of 40 ° C.

15.75 g of siliconyl beeswax sold by Koster Keunen (Tfi = 75 ° C) are mixed with 47.25 g of silicone oil sold by v W r (Tf ² <0 ° C). The mixture is stirred and heated to a temperature of about 90 ° C.

This liquid ternary mixture (at a temperature between T f and 80 ° C) is introduced into the aqueous solution of the HASE copolymer using a peristaltic pump.

Coacervation

6.44 g of a ^{4% H 3} PO ⁴ solution are added to the aqueous HASE copolymer solution to which the liquid ternary mixture has been added. A dispersion that is white in color is obtained.

EXAMPLE 3

This example illustrates the preparation of two microparticle dispersions according to the invention with terpineol as the active ingredient.

Preparation of the acrylic copolymer HASE

The acrylic copolymer according to the invention is prepared according to procedures known to a person skilled in the art by means of a mercaptan-type chain transfer agent.

This co-polymer is made of:

35.5% by weight of methacrylic acid,

52.4% by weight of ethyl acrylate,

12.0% by weight of a macromonomer of formula (I) in which:

- m and p = 0,

- n = 30,

- R represents a methacrylic ester,

- R 'represents a branched hydrocarbon chain comprising 12 carbon atoms.

Test 3-1: Preparation of a microparticle dispersion according to the present invention Preparation of an aqueous solution

7.5 g of HASE co-polymer (polymerized at 30.8% in water) are dissolved in 59.25 g of water in the presence of 3.8 g of 10% sodium hydroxide solution by mixing in a mechanical mixer at a temperature of 40 ° C.

7.88 g of paraffin wax sold by Sigma-Aldrich (Tfi = 53 at 57 ° C) are mixed with 7.88 g of commercial wonder oil and 47.25 g of terpineol (Sigma-Aldrich). The mixture is stirred and heated to a temperature of about 80 ° C.

This liquid ternary mixture (at a temperature between Tfi and 80 ° C) is introduced into an aqueous solution of HASE copolymer using a peristaltic pump.

Coacervation

6.44 g of a ^{4% H 3} PO ⁴ solution are added to the aqueous HASE copolymer solution to which the liquid ternary mixture has been added. A dispersion which is white in color, the particle diameter D50% of which is 2.73 pm, is obtained.

Test 3-2: Preparation of a dispersion of microparticles outside the invention

Preparation of an aqueous solution

7.5 g of HASE co-polymer (polymerized at 30.8% in water) are dissolved in 59.25 g of water in the presence of 3.8 g of 10% sodium hydroxide solution by mixing in a mechanical mixer at a temperature of 40 ° C.

15.75 g of paraffin wax sold by Sigma-Aldrich (Tfi = 53 at 57 ° C) are mixed with 47.25 g of terpineol (Sigma-Aldrich). The mixture is stirred and heated to a temperature of about 80 ° C.

This liquid ternary mixture (at a temperature between Tfi and 80 ° C) is introduced into the aqueous HASE copolymer solution using a peristaltic pump.

Coacervation

6.44 g of a ^{4% H 3} PO ⁴ solution are added to the aqueous HASE copolymer solution to which the liquid ternary mixture has been added. Lumps, the diameter D50% of 29.7 pm, is obtained.

Claims (8)

1. Microparticles having a polymeric shell, comprising , based on the total weight of the microparticles: a) from 1 to 20% by weight of at least one acrylic copolymer of the HASE type comprising: - at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group; - at least one hydrophobic nonionic monomer having a vinyl group capable of being polymerized; and - at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and a hydrophobic hydrocarbon chain; b) from 4 to 95% by weight of at least one solid / liquid phase change material that has a phase transition temperature Tfi varying from 35 ° C to 90 ° C, selected within the waxes of natural origin, waxes of synthetic origin or mixtures thereof; c) from 4 to 95% by weight of at least one solid / liquid phase change material having a phase transition temperature Tf ² less than or equal to 30 ° C, for example less than or equal to 20 ° C , selected from the group consisting of vegetable oils, fatty alcohols, fatty acids, and mixtures thereof; and d) optionally, 4 to 95% by weight of an active agent selected from the group consisting of fragrance molecules, flavors, opacifying agents, moisturizing agents, softening agents, cooling agents, tinctures, plasticizers, slimming agents, active ingredients. pharmaceuticals, inks, pigments, agrochemical active ingredients, herbicides, antiseptics, detergents, enzymes, antifoaming agents, whitening agents, optical brighteners, biocides, UV stabilizers, antioxidants, corrosion inhibitors, fungicides and antibacterial agents. 2. Microparticles according to claim 1, in which the material is chosen from waxes of natural origin, waxes of synthetic origin or mixtures thereof, having a phase transition temperature Tf1 varying from 35 ° C to 80 ° C, advantageously 35 to 70 ° C. Microparticles according to any of the preceding claims, in which the HASE type acrylic copolymer comprises, based on the total weight of said copolymer: i) from 20% to 65% by weight of at least one anionic monomer having a vinyl group capable of being polymerized and a carboxyl group; ii) from 35% to 75% by weight of at least one hydrophobic nonionic monomer having a vinyl group capable of being polymerized; Y iii) from 0.5% to 15% by weight of at least one alkoxylated associative macromonomer having a vinyl group capable of being polymerized and having a hydrophobic hydrocarbon chain. 4. Microparticles according to any of the preceding claims, in which the at least one alkoxylated associative macromonomer iii. Of the HASE-type acrylic copolymer has a formula (I): (I) R - A - R ' in which: - A represents a polymer chain consisting of: - m alkylene oxide units of the formula -CH ² CHR ¹ O- with R ¹ representing an alkyl group comprising 1 to 4 carbons, and m varying from 0 to 150, - p alkylene oxide units of the formula -CH ² CHR ² O- with R ² representing an alkyl group comprising 1 to 4 carbons, and p varying from 0 to 150, - n units of ethylene oxide with n varying from 0 to 150, in which m + n + p> 4 and in which the alkylene oxide units of the formula -CH ² CHR ¹ O-, the alkylene oxide units of the formula -CH ² CHR ² O- and the oxide units of ethylene are in blocks, staggered or randomly; - R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic or crotonic esters; Y - R 'represents a straight or branched hydrocarbon chain comprising from 6 to 40 carbon atoms or a substituted or unsubstituted cycloalkyl or aryl group comprising from 6 to 100 carbon atoms. Microparticles according to claim 4, in which the associative alkoxylated macromonomer iii., Of formula (I) is such that: - m and p represent 0, respectively, - n ranges from 15 to 150, - R represents a radical containing an unsaturated group capable of being polymerized belonging to the group of acrylic, methacrylic, maleic, itaconic or crotonic esters; Y - R 'represents a straight hydrocarbon chain comprising 8 to 22 carbon atoms or a branched alkyl chain comprising 12 to 20 carbon atoms. 6. Aqueous dispersion characterized in that it comprises microparticles as claimed in any of the preceding claims. 7. Use of the microparticles according to claims 1 to 5 or of aqueous dispersions of microparticles according to claim 6, to make hydrophobic textiles. 8. Use of the microparticles according to claims 1 to 5 or of aqueous dispersions of microparticles according to claim 6, to release an active agent in response to a change in pH, a change in temperature and / or frictions.